Apple could be in the process of developing the technology necessary to integrate solar panels into its portable electronic devices, leading some to claim that an eco-friendly iPhone is not too far away.

Apple has allegedly filed for patents which would cover solar technology being added to touch screen displays. This would allow the outer design of the iPhone to remain intact and unchanged by the new power source, but would boost its green credentials and keep it operational without the need for a recharge for much longer.

According to sources, Apple is looking into sandwiching a layer which would draw energy from sunlight in between the touch screen technology and the pixels of the display itself. This would make the solar panel completely invisible and would allow Apple to continue to create beautiful electronic devices without compromising their design.

Solar panel technology has been used to power electronic devices for years and other mobile phone manufacturers have already taken advantage of it as a secondary power source. The LG GD510 Pop, for example, was shown in all of its promotional material as coming with an interchangeable battery cover complete with a solar panel, although LG has since said that this accessory will not make it to market until later in the year.

Apple will be the first mobile manufacturer to attempt to disguise their solar panel, although some have predicted that it could compromise the responsiveness of the touch screen and others have said that the cost of the new technology could make it too expensive for general sale.